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1. Sustainability in architecture
and construction
Building level

2. 1. Materials Selection: Choose materials that have a lower environmental impact, such as recycled
or reclaimed materials, natural materials like wood or bamboo from sustainable sources, and
materials with high levels of recyclability or biodegradability.
Enviromate in the
UK, Loopfront in Norway,
Freegle & Freecyle.

3. 2. Energy Efficiency: Design buildings with energy-efficient systems and features, such as
insulation, energy-efficient HVAC systems, LED lighting, and renewable energy sources like solar
panels or wind turbines.
3. Water Conservation: Implement water-saving technologies such as rainwater harvesting
systems, greywater recycling, and low-flow fixtures to reduce water consumption.

4. 4. Waste Management: Develop a comprehensive waste management plan to minimize
construction waste and promote recycling and reuse of materials during and after construction.
5. Passive Design Strategies: Incorporate passive design strategies such as orientation for natural
light and ventilation, thermal mass, and shading elements to reduce the building's reliance on
mechanical systems for heating, cooling, and lighting.

5. 1. Orientation: Properly orienting a building with respect to the sun's path is fundamental. In hot
climates, orienting the building to minimize direct sunlight exposure during the hottest parts of the
day can reduce cooling loads. Conversely, in cold climates, maximizing south-facing windows can
capture more sunlight for passive heating.
2. Natural Ventilation: Designing for natural ventilation involves strategically placing openings such
as windows, doors, and vents to facilitate cross ventilation and airflow throughout the building. This
helps remove stale air, reduce humidity, and maintain a comfortable indoor environment.
3. Shading: Incorporating shading devices such as overhangs, awnings, louvers, or external blinds
can block direct sunlight from entering windows during hot periods while allowing sunlight in during
cooler times. This reduces the need for artificial cooling and prevents excessive heat gain.
4. Thermal Mass: Using materials with high thermal mass, such as concrete, brick, or stone, in the
building's structure can absorb and store heat during the day and release it gradually at night,
helping to stabilize indoor temperatures and reduce temperature fluctuations.

6. 5. Insulation: Proper insulation in walls, floors, and roofs prevents heat transfer between indoor
and outdoor environments, reducing the need for heating and cooling. High-quality insulation
materials like foam, fiberglass, or cellulose can significantly improve energy efficiency.
6. Daylighting: Maximizing natural daylight through well-placed windows, skylights, and light wells
not only reduces the need for artificial lighting but also creates a more pleasant and productive
indoor environment. Designing spaces with ample natural light can also enhance occupants' well-
being.
7. Green Roofs and Walls: Green roofs and walls, which are covered with vegetation, provide
additional insulation, absorb rainwater, reduce heat island effects, and improve air quality. They can
contribute to energy savings and enhance the building's overall sustainability.
8. Natural Landscaping: Incorporating native plants, trees, and landscaping features around the
building can provide shade, reduce heat absorption from the ground, and create microclimates that
enhance comfort and energy efficiency.

7. 9. Cool Roofs: Cool roofs are designed to reflect more sunlight and absorb less heat compared to traditional roofs.
They can be made of reflective materials like white membranes, tiles, or coatings that reduce heat gain, especially in
hot climates, and lower cooling energy demand.
10. Natural Materials: Utilizing natural and locally sourced materials in construction can reduce embodied energy
(energy used in material extraction, manufacturing, and transportation). Materials like rammed earth, straw bales,
clay, and timber from sustainable forests can be used for walls, floors, and finishes.
11. Thermal Chimneys: Thermal chimneys, also known as stack ventilation, use the principle of hot air rising to
create natural airflow within a building. Placing vertical shafts or chimneys in strategic locations allows hot air to
escape, drawing in cooler air from lower levels and improving natural ventilation.
12. Passive Solar Design: Passive solar design maximizes the use of solar energy for heating and lighting. This includes
designing buildings with large south-facing windows to capture sunlight, using thermal mass to store heat, and
incorporating shading devices to control solar gain based on seasonal variations.
13. Decentralized Ventilation: Instead of centralized HVAC systems, decentralized ventilation systems can be
implemented, such as individual room ventilation units or energy recovery ventilators (ERVs). These systems provide
targeted ventilation, improve indoor air quality, and reduce energy consumption compared to centralized systems.
14. Hybrid Systems: Combining passive design strategies with active systems, such as solar panels for electricity
generation, solar water heaters, or geothermal heat pumps, can create hybrid solutions that maximize energy
efficiency and sustainability while meeting specific building requirements.
15. Building Form and Layout: The overall form and layout of a building can influence its energy performance.
Compact building designs with efficient floor plans reduce exterior surface area, minimizing heat loss or gain.
Additionally, designing for natural daylight penetration throughout the building's interior reduces reliance on artificial
lighting.
16. Occupant Behavior: Educating occupants about sustainable practices, such as adjusting thermostat settings,
using natural ventilation when possible, and turning off lights and equipment when not in use, can complement
passive design strategies and further reduce energy consumption.

8. Air conditioner – Basic working principle

9. Direct vs indirect cooling

10. Multistage evaporative cooling system
A multi stage
evaporative cooling
system can work
according to the
humidity of ambient
and humidity desired
for supply air. When
the relative humidity of
ambient air is high,
only indirect cooling
can be used. This
reduces the air
temperature of supply
air, but the humidity
remains unchanged.
When increase in
humidity is also
desired, as in dry hot
seasons, direct
evaporative cooling
can be used.

11. Desiccant Cooling System
These systems are used
in applications where the
latent heat load is too
high i.e. moisture
content desired in supply
air is minimal. Energy is
saved by using the
desiccant to absorb or
adsorb the moisture
content instead of
mechanical equipment.
Mechanical energy is
then needed only for
reducing the temperature
of the air.

12. • Two stage evaporative cooling systems (direct + indirect) – the direct system
could be functional during the dry season, when humidification of air is required,
used when air primarily needs to be cooled.
• Three stage evaporative cooling system (direct + indirect + cooling coil) consists
of direct and indirect evaporative cooling together with conventional cooling coil.
(chilled water or refrigerants) is helpful in monsoon season when the humidity
dehumidification is required. Fresh air passed through the coils controls both
requirements. The coils are also useful in winter season when some heating is
• The drawback of the two stage system is the high humidity level of the supply
indirect evaporative cooling systems which provide sensible cooling of the air
emerged in the market.

13. Tri-Generation (Waste to Heat)
Trigeneration systems
produce heat and
electricity which in turn
can be used for heating,
cooling and hot water
heating systems in a
building. Electricity
produced can also be
supplied to the grid if not
needed on the site.
Trigeneration systems are
more commonly used in
buildings with readily
available waste heat and
intense 24 hours
operations.

14. solar air conditioning system
Typically vapor absorption machines or chillers are used in solar conditioning. Energy is
saved by using the heat generated from the solar panels to regenerate the absorbent in
the chiller.
Absorption chillers comprise of the
following components:
1.Evaporator: where the refrigerant
evaporates at a very low pressure and
temperature and is absorbed by the
absorbent. The process results in
extraction of heat from the refrigerant
and provides chilled refrigerant as an
output.
2.Generator: The mixture of
absorbent and refrigerant is then
introduced in the generator. Steam or
hot water produced through the solar
panel devices is used to vaporize
refrigerant.
3.Condenser: The vaporized
refrigerant will be cooled down in
condenser and maintained at low
pressure. This cooled refrigerant will
be further used in evaporator for
generation of chilled water for air
conditioning.

15. Radiant cooling system
Pipes embedded in
the structure cool or
heat the thermal
mass of the building
generally during the
hours when it is
unoccupied. For
cooling, radiant
systems use both
thermal mass and
nocturnal cooling.
Chilled water in the
pipes can be
supplied through a
conventional chiller.

16. Heat recovery ventilator (HRV)
• Rotary enthalpy wheel
• Fixed plate
• Heat pipe
• Run around coil
• Thermosiphon
• Twin towers

17. Ground source heat pumps
Ground source heat pumps use the earth as a heat sink if a building is to be cooled and as a heat source
if a building is to be heated. Temperatures at a certain depth from the surface are nearly constant
through the year, and this temperature differential is utilized by the heat pumps to cool or heat the
refrigerant in a conventional vapour compression cycle.

18. Shared ground heat exchange
can deliver low-carbon
electrified heat where
individual heat pumps or heat
networks are not feasible,
such as in terraced homes.
However, there is a policy gap
around these mid-scale heat
solutions. We outline the
benefits and challenges of
shared ground heat exchange,
and actions needed by policy,
housing, and innovation
stakeholders to support
further deployment.

19. A Ground Source Heat Pump (GSHP) system heats and cools building by using earth as a heat source or
heat sink. The system either extracts thermal energy out of the ground or transfers thermal energy from
buildings to the ground. Moreover, heat energy stored during the summer season could be extracted out
during winters to heat the ambient spaces. On average, 46% of the total solar energy received is stored.
At 4-6 meters below ground surface, temperatures are more or less constant. Heat could be pumped in
during summers to the ground, where the temperature is lower than the ambient temperature. GSHP
system has three major components:
1. Earth Connection:
Earth connection is the connection between the GSHP system and the soil. Most popular connections
are tubes, introduced either horizontally or vertically into the ground, or submerged in a lake or pond.
The tubes carry an anti-freeze mixture and a suitable type of heat transfer fluid.
2. Heat pump:
Heat pump helps heat transfer from fluid in the earth connection to the distribution system. The heat
pump consists of a heat carrier like water or air, which absorbs heat from heat transfer fluid through
indirect contact and subsequently carries this heat energy to the heating/ cooling distribution system.
In a reverse cycle, the heat carrier transfers heat from the distribution systems to the heat transfer fluid
in the earth connection.
3. Heating/ cooling distribution system:
This system delivers the heating or cooling from the heat pump to the ambient spaces. It consists of air
ducts, diffusers, fresh air supply systems and control components, and circulates the supply air as per
design conditions and occupants requirements.
• Depth below ground surface where temperatures are nearly constant is valid for India. It varies by
latitude.

20. Renewable energy systems

21. • The process of generation of electricity
from solar cells is a two – step process.
• The first step is the physical process and
involves the photoelectric effect in which
the photons strike the metal surface and
provide energy to the electrons in the
metal.
• The next step involves the electrochemical
process in which the excited electrons are
arranged in a series, thereby creating an
electric voltage and generating electric
current. The generated electricity can
either be consumed instantaneously on
site, stored in batteries for later use, or
sold to power utilities according to local
government regulations and prevalent
tariffs.

22. • Solar Energy Deployment
• Based on the availability of space and capital, solar energy can either be generated offsite at
Both types of generation mechanisms are guided by their own rules and policy frameworks.
• Utility driven solar project development – These are large scale centralized solar power plants
which generate electricity to be sold to power utilities. These plants require large tracts of land
plants usually have a long term Power Purchase Agreement (PPA) with the power utility and
Renewable Purchase Obligations (RPO).
• Customer driven solar project development – These are small scale decentralized solar power
plants installed by electricity consumers in their own premises. These type of projects require
These systems are further divided into two parts:
• Grid Connected Systems – Grid connected PV systems are designed to work in conjunction
with the utility grid. Such systems can either supply the complete generated electricity to
for building use and supply only the excess power to the grid.
• Stand – alone systems – Stand – alone PV systems are designed to operate within the
context of the building and are not connected to the grid. The electricity generated is
excess energy generated can be stored in the batteries for future use.

23. • Solar electricity generation system
• A complete solar electricity generation system consists of components to produce electricity, convert
used by equipment installed in the building, and store excess generated electricity (for those systems
generated electricity to grid).
• Solar PV panels – Solar panels are the basic part of a solar electricity generation system. These panels
consist of numerous solar cells which are made up of a semiconducting material. These solar cells are
incident light into usable electricity. Although the sizes may vary according to generation capacity,
of the solar panel ranges between 65 inches and 77 inches and the breadth ranges between 35 inches
of solar panels ranges from 1.4 inches to 1.8 inches.
• Inverter – The inverter converts the DC produced by the solar panels into AC that can be fed into the
grid or used for the operation of electrical appliances. Additionally, the inverter acts as a safety valve
electricity mains.
• Storage Batteries – Storage batteries are used to store excess electric energy generated by the PV
system for future use. Batteries are typically employed in PV systems which do not intend to sell
• Electricity Meter – The meter counts the number of units of electricity generated by the PV system.
They are essential for calculating the proceeds from the sale of electricity to the grid.

24. • Factors affecting generation of electricity
• Solar cell efficiency is the ratio of electrical output to the incident solar energy. Major factors
• Location, tilt, and orientation – The incident solar radiation varies significantly with longitude
and orientation. Within a particular longitude and orientation, maximum solar radiation is
on sun path.
• Over shading – Site characteristics like geography, neighbouring buildings, self-shading, cloud
factors etc. affect the useful solar radiation falling on the PV panels. System design should be
affected by shading.
• Temperature – An increase in panel temperature due to solar radiation can affect the PV module
performance especially in crystalline silicon modules. It is estimated that for every 1 0C increase
25 0C, the PV module performance decreases in the range of 0.4 – 0.5%. Special considerations
over the backs of the PV modules to avoid higher temperature by excessive heat gains.
• Panel efficiency – Panel efficiency is an estimate of successful conversion of incident solar
radiation to electric energy. Panel efficiency depends on PV module technology, manufacturing
crystalline silicon based module has an efficiency in the range of 12-14% where as a thin film
the range of 10 – 11%.

25. Wind power is generated by using wind turbines
to harness the kinetic energy of wind. Wind
blowing across the rotors of a wind turbine
causes them to spin. The spinning of rotors
converts a portion of the kinetic energy of the
wind into mechanical energy. A generator
further converts this mechanical energy into
electricity.
Wind power can be generated at utility scale,
offshore location and at distributed or small
scale. Utility scale wind power uses turbines
larger than 100 kilowatts to deliver power to the
grid. Offshore wind power, as the name implies,
is generated by installing large turbines at
offshore locations. Distributed wind power is
produced from turbines of 100 kilowatts or less
and supply power directly to a home or building
or for running any machine.

26. • Horizontal axis wind turbines (HAWT) continually face in
the direction of wind and are lift driven machines. Rotors
in a HAWT can be in front of the tower on which it is
supported and facing the wind (windward), or behind it
and away from the wind (leeward). Rotors or blades in
most horizontal axis turbines are placed upwind to the
tower. Horizontal wind turbines are equipped with sensors
which determine both the direction and velocity of the
wind. Number of rotors may vary but 2-3 rotors are the
most efficient configuration and most easily available.
• Vertical axis wind turbines (VAWT) are not dependant on
the wind direction and are more suitable for area of highly
variable wind direction. Shaft containing the gearbox,
generator etc. is vertical. Consequently they are more
suitable for distributed generation in buildings. Generator
and gearbox is installed on the ground for vertical turbines
which renders them easier for maintenance. Darrieus or
egg beater is a lift force driven vertical axis turbine
and Savonius is a drag driven type of vertical axis turbine.
Savonius wind turbines are the most widely used drag
type turbines because of their robustness.

27. Biomass energy is the
energy obtained from plants
or plant-derived materials.
Wood is the most widely
used source of biomass
energy. Other sources of
biomass include: terrestrial
and aquatic plants,
agricultural wastes, industrial
residues, sewage sludge,
animal and municipal
wastes.
There are three major
technologies used for
conversion of biomass into
useful energy:

28. • Biomass Gasification
In this, a thermo-chemical process is used to convert biomass to producer gas. Producer gas is a
mixture of Carbon monoxide (CO), Hydrogen (H2), Methane (CH4), Carbon dioxide (CO2) and
Nitrogen (N2). The sources of biomass in this include wood and its products as well as various
agricultural residues. Upon gasification, this can lead to power generation in the range of 10 kW –
1000 kWe. The energy produced can also be used for thermal application in small industries up to
3 MW.
• Biogas
In this, Bio-methanation process is used to convert biomass to biogas. Animal dung is commonly
used in production of biogas. The Biogas produced can be used for cooking in households as well
as for electricity generation.
• Biofuels
The process of trans-esterification is used for production of bio-diesel. Bio-oil is also extracted
from oil seeds. The source for biofuels is non edible vegetable oil seeds. Biofuels are used for
electricity generation as well as motive power.
• The use of biomass energy greatly reduces dependence on fossil fuels. The products used for
conversion of biomass to energy are abundant in nature and the energy is renewable in nature.
Biomass being a clean energy resource receives various tax benefits from the government.

29. Phase change material PCM